Field of the Invention and Related Art Statement
The present invention relates to a shutter mechanism for use in a recording and/or reproducing apparatus using a card-like record medium such as a magnetic card and optical card. In the present specification, for the sake of simplicity, the above mentioned recording and/or reproducing apparatus is sometimes called a card recording and/or reproducing apparatus, and the card-like record medium is called a record card.
In the card recording and/or reproducing apparatus, there is provided a guide slot in a front wall of the apparatus and through said guide slot a record card is inserted into the apparatus and discharged from the apparatus. A movable shutter is provided at the guide slot in order to prevent dust particles from being introduced into the apparatus.
FIG. 1 shows a known shutter mechanism disclosed in Japanese Patent Application Laid-open Publication Kokai Sho 62-124,687. In this known shutter mechanism, a guide slot 101 is provided at a front wall of a card recording and/or reproducing apparatus and a rod 102 serving as a shutter is arranged within the guide slot 101 such that the rod is resiliently urged by a leaf spring 103 against a lower wall 105 along which a record card 104 is fed. As illustrated in FIG. 2A, when the record card 104 is inserted into the apparatus through the guide slot 101, the rod 102 is engaged with a front end of the record card 104 and is pushed upward against the force of the leaf spring 103. The card recording and/or reproducing apparatus comprises a card feeding device such as a driving roller mechanism and the record card is fed forwardly. When the record card 104 is discharged from the apparatus by feeding the record card backwardly by means of the card feeding device, a rear end of the record card is engaged with the rod 102 and the rod is pushed upward.
In the above mentioned known shutter mechanism, upon inserting the record card 104 into the apparatus, after the front end of the record card has been urged against the rod 102, the record card has to be pushed forward by a relatively strong force such that the rod is moved upward against the force of the leaf spring 103. In this case, the insertion angle, insertion speed, insertion force and other factors might vary for each respective inserting operations as well as users, so that there might be produced a large repelling force in the record card 104 and the record card might be bent or curved. When the record card 104 is curved, the rear end of the record card might be urged against the rod 102 at its relatively upper portion as illustrated in FIG. 2B, and thus the rod could not be pushed upward effectively. In this manner, the record card 104 might not be discharged from the card recording and/or reproducing apparatus.
In Japanese Patent Application Laid-open Publication Kokai Sho 60-247,881, there is described another known shutter mechanism. As shown in FIGS. 3A, 3B and 3C, behind a guide slot 111 there is arranged a shutter 112 swingably about a shaft 113 both forwardly and backwardly. There is further provided a spring 114 for keeping the shutter in the upright position shown in FIG. 3A. Upon inserting a record card 115 into the apparatus, a front edge of the record card 115 is engaged with a front surface of the shutter 112, so that the shutter is rotated in the counter-clockwise direction as illustrated in FIG. 3B and the record card is fed by means of a pair of feeding rollers 116 forwardly. When the record card 115 is discharged from the apparatus, a rear edge of the record card is engaged with a rear surface of the shutter and the shutter 112 is rotated in the clockwise direction. This known shutter mechanism has a drawback that it is necessary to provide a relatively large space behind the guide slot 111, because the shutter is swung both in the clockwise and counter-clockwise directions. Moreover, the shutter 112 has to be separated from the guide slot 111 in the normal position, the guide slot could not be effectively closed by the shutter, so that dust might be introduced into the apparatus. The above mentioned drawbacks may be removed by providing an electromagnetic actuator for moving the shutter, but in this case the cost of the shutter mechanism might be increased.